The invention relates to systems and methods for securely transferring data between a local storage area and a remote storage area. Many systems and schemes have been devised to “backup” important information on various storage media, i.e. maintain another copy of the information so that the information may be restored should the original copy of the information become damaged or otherwise unavailable. Unfortunately, backup media rarely receive the same protection and attention as the original data itself. Despite the critical nature of backup in recovering from loss due to accidental or malicious failure, it is one of the most overlooked processes when it comes to site security.
Most backup techniques today involve transferring data over a network, which thereby renders the backup data vulnerable to attack at several points. There are several commercial products that offer network-based backup services. See, e.g., backup.com, BitSTOR.com, backjack.com, datalock.com, systemrestore.com, trgcomm.com, sgii.com, veritas.com/us/products/telebackup. The most common technique for protecting backups is to encrypt files locally using a key derived from a passphrase. While such services range in features and in style of architecture, unfortunately, none of them are well-designed from the security point-of-view. Many are in fact insecure as well as inefficient and do not provide the proper level of data authentication and confidentiality.